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Thu Kha Kyawe
Thu Kha Kyawe

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2.Ansible Install Package

Task Information

The Nautilus Application development team wanted to test some applications on app servers in Stratos Datacenter. They shared some pre-requisites with the DevOps team, and packages need to be installed on app servers. Since we are already using Ansible for automating such tasks, please perform this task using Ansible as per details mentioned below:

Create an inventory file /home/thor/playbook/inventory on jump host and add all app servers in it.

Create an Ansible playbook /home/thor/playbook/playbook.yml to install wget package on all  app servers using Ansible yum module.

Make sure user thor should be able to run the playbook on jump host.
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Task Solutions

βœ… Part 1: Lab Step-by-Step Guidelines (Technical & Precise)

Step 1: Generate SSH Key on Jump Host (as thor)

ssh-keygen
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Step 2: Copy Public Key to Each App Server

Run:

ssh-copy-id tony@172.16.238.10
ssh-copy-id steve@172.16.238.11
ssh-copy-id banner@172.16.238.12
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Enter respective passwords when prompted:

Ir0nM@n

Am3ric@

BigGr33n

Step 3: Create Playbook Directory

mkdir -p /home/thor/playbook
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Step 4: Create Inventory File

Create inventory file:

vi /home/thor/playbook/inventory
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Add all app servers under a group (example format below):

[app_servers]
stapp01 ansible_host=172.16.238.10 ansible_user=tony ansible_become=yes
stapp02 ansible_host=172.16.238.11 ansible_user=steve ansible_become=yes
stapp03 ansible_host=172.16.238.12 ansible_user=banner ansible_become=yes
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Save and exit.

Step 5: Create Ansible Playbook

vi /home/thor/playbook/playbook.yml
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Add the following YAML configuration:

---
- name: Install wget on app servers
  hosts: app_servers
  become: yes
  tasks:
    - name: Install wget package
      yum:
        name: wget
        state: present
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Save and exit.

Step 6: Verify Permissions for thor

Ensure thor owns the files:

ls -l /home/thor/playbook
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If needed:

chown -R thor:thor /home/thor/playbook
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Step 7: Run the Playbook as thor

ansible-playbook -i /home/thor/playbook/inventory /home/thor/playbook/playbook.yml
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Step 8: Verify Installation on App Servers

You can verify using:

ansible app_servers -i /home/thor/playbook/inventory -a "rpm -q wget"
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Expected output:

stapp03 | CHANGED | rc=0 >>
wget-1.21.1-8.el9.x86_64
stapp02 | CHANGED | rc=0 >>
wget-1.21.1-8.el9.x86_64
stapp01 | CHANGED | rc=0 >>
wget-1.21.1-8.el9.x86_64

🧠 Part 2: Simple Step-by-Step Explanation (Beginner Friendly)

πŸ” Step 1: Generate SSH Key
ssh-keygen
What this does:

This creates a secure digital key pair:

A private key (kept on the jump server)

A public key (copied to other servers)

Think of it like:

πŸ”‘ Private key = your secret house key

πŸ”“ Public key = a lock installed on each app server

When you try to connect, the server checks:

β€œDoes this key match the lock I have?”

If yes β†’ You’re allowed in without typing a password.

This is more secure and more professional than storing passwords.

πŸ“€ Step 2: Copy Public Key to App Servers
ssh-copy-id tony@172.16.238.10
What this does:

It installs your public key onto the app server.

After this:

The jump host (thor) can connect to that server

No password is required anymore

You repeat this for all three app servers.

Now Ansible can log in automatically.

πŸ“ Step 3: Create Playbook Directory
mkdir -p /home/thor/playbook
What this does:

Creates a folder to store:

The server list (inventory)

The automation instructions (playbook)

This keeps everything organized.

πŸ“‹ Step 4: Create Inventory File
vi /home/thor/playbook/inventory
What is the inventory?

The inventory is:

A contact list of servers Ansible should manage.

Example:

[app_servers]
stapp01 ansible_host=172.16.238.10 ansible_user=tony ansible_become=yes

This tells Ansible:

Connect to IP 172.16.238.10

Login as user tony

Use sudo privileges (become root)

You grouped all three servers under:

[app_servers]

So when Ansible runs, it targets all three at once.

πŸ“œ Step 5: Create the Playbook
vi /home/thor/playbook/playbook.yml
What is a playbook?

A playbook is:

A list of instructions telling Ansible what to do.

Your playbook says:

Go to all servers in app_servers

Become root

Install wget

Make sure it is present

The important part:

yum:
name: wget
state: present

This means:

β€œIf wget is not installed β†’ install it.
If it’s already installed β†’ do nothing.”

That makes it safe and repeatable.

πŸ” Step 6: Verify File Ownership
ls -l /home/thor/playbook

This ensures:

thor owns the files

thor can execute the playbook

If files belong to another user, Ansible might fail.

β–Ά Step 7: Run the Playbook
ansible-playbook -i inventory playbook.yml

What happens behind the scenes:

For each server:

Ansible connects using SSH key

Switches to root using sudo

Runs the equivalent of:

sudo yum install wget

Moves to the next server

Reports status

All automatically.

πŸ”Ž Step 8: Verify Installation
ansible app_servers -a "rpm -q wget"

This checks:

β€œIs wget installed?”

Output:

wget-1.21.1-8.el9.x86_64

That means installation was successful.

🎯 What You Just Accomplished

Without logging into each server manually, you:

Connected securely using SSH keys

Installed software on 3 servers at once

Verified installation

Used proper DevOps automation practice

πŸ’‘ Why This Matters in Real DevOps

Instead of:

Logging into 50 servers one by one

You can:

Run one command

Update all servers instantly

That is the power of Ansible automation.


Resources & Next Steps
πŸ“¦ Full Code Repository: KodeKloud Learning Labs
πŸ“– More Deep Dives: Whispering Cloud Insights - Read other technical articles
πŸ’¬ Join Discussion: DEV Community - Share your thoughts and questions
πŸ’Ό Let's Connect: LinkedIn - I'd love to connect with you

Credits
β€’ All labs are from: KodeKloud
β€’ I sincerely appreciate your provision of these valuable resources.

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